Explosively actuated driving tool



Aug. 7, 1962 w. E. SCHULZ EXPLOSIVELY ACTUATED DRIVING TOOL Fil ed June 20, 1955 Fig. 1

tates The present invention relates to explosively actuated driving tools for driving studs, nails or the like into walls, ceilings and other bodies. This application is a continution-in-part application of my co-pending application Ser. 369,870, filed July 23, 1953, now abandoned.

It is an object of this invention so to reduce the recoil encountered with heretofore known explosively actuated driving tools so that hand injuries of the person operating the tool will be safely avoided.

It is another object of this invention to provide an explosively actuated driving tool in which the recoil is made ineffective in order to avoid the danger that a person operating the tool while working on a high scafiold or ladder will fall from such scaffold or ladder due to the recoil of the tool.

A further object of the invention consists in the provision of an explosively actuated driving tool which will make it possible to vary the driving power of the tool so that while using the same type of cartridges nails, studs, or the like of different lengths and thicknesses may be driven into the respective body or into bodies of different material.

It is also an object of this invention to provide an explosively actuated driving tool which cannot be used as a firearm and in which the release of a shot is possible only when the muzzle of the barrel is firmly pressed against a resistance so that the barrel is displaced in axial direction thereof.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings in which:

FIG. 1 illustrates a diagrammatic longitudinal sectional view of an embodiment of an explosively actuated driving tool in accordance with the invention with means for varying the driving power.

FIGS. 2 and 3 respectively illustrate two different positions of the control arrangement forming part of the tool according to FIG. 1.

FIG. 4 represents a cross section through FIG. 1 taken along the line IV-IV of FIG. 1.

It is a general requirement that driving tools in order to meet all possible situations occurring in practice may be able to use studs of different size. Furthermore, even when using the same type and size of studs, the driving power must be variable so that studs may be shot into very hard as well as into very soft material and to a varying degree. In order to be able to drive studs of different sizes, it is understood that barrels of difierent inner diameter have to be inserted into the driving tools. Heretofore, it was customary also to provide different size cartridges, i.e. cartridges having a driving charge of different magnitude. This, however, has proved undesirable because it forces the operator handling such driving tools to carry along a considerable supply of different cartridges. The arrangement according to FIG. 1 represents a driving tool according to the invention which makes it possible with one and the same cartridge to drive not only studs of different diameters but also studs of the same diameter at different force, i.e. into different depths.

While it has been suggested to introduce a stud more or less deeply into the barrel in order to be able to drive such stud at different power while using the same cartridge, and while it has also been proposed for the same purpose to provide the tool with a variable opening to allow powder atent l anemia Fatented Aug. 7, 1962 gases to escape therethrough from the barrel, experience has shown that these arrangements are either not practical or not sufliciently effective.

According to the embodiment shown in FIG. 1, the casing consists of a tubular section 161 which is fixedly connected with the handle 119 and which houses the breech block 162 as well as the release mechanism for the firing pin '165. The breech block 162 is continuously urged forwardly by means of a spring 172 which rests against the top 200 of the casing 161. When the breech block occupies its foremost position, its shoulder abuts the ring 159 inserted in the casing. This ring limits the forward movement of the breech block 162.. The ring 159 is adapted to slide backwardly against the thrust of the spring 158 which has one end in engagement with the ring 159 while its other end engages a shoulder of the breech block 162. A ring 167 is arranged within the breech block 162 in such a manner that it is slidable in a direction transverse to the longitudinal direction of the tool. The longitudinal bore of ring 167 is provided with a shoulder against which abuts the front surface of the collar 168 of firing pin 165, while the rear surface of said collar 168' is engaged by the front surface of the sleeve 157. Sleeve 157 is slipped over the hollow stud 182 in a telescopic manner. The hollow stud 182 in its turn is fixedly connected to the top 200 of the casing 161. The end of the firing pin is passed through a bore in the front end of the hollow stud 182, and a nut 156 screwed on or welded to the firing pin prevents the firing pin from leaving the stud 182 and thus limits the forward movement of the firing pin which by means of the firing pin spring 166 is continuously urged forwardly. The ring 167 is provided with a pin 171 arranged when releasing the shot to cooperate with a nose of the trigger 169.

The breech block 162 has a lateral groove 155 into which extends a roller 173 which latter is arranged to roll on an incline 174 forming the bottom of a groove 201 in a member mounted in handle 119. A pin 18!) mounted slidably in casing 161 continuously urged forwardly by a spring 202 is arranged to press the roller 173 forwardly which in this manner together with the groove 15S and the inclined surface 174 forms a friction locking mechanism. This locking mechanism allows a rearward movement of the breech block 162 whereas it impedes the forward movement of the breech block.

The casing 161 of the driving tool furthermore slidably mounts a pin 179 which when breaking the front portion 175 of the casing will be pressed rearwardly due to a cam 178 on the front portion 175 of the casing so that the pin 179 will engage the roller 173 thereby releasing said friction locking mechanism.

The front portion 175 of the casing consists of a tube which by means of a hinge 176 is pivotally connected with the rear portion 161 of the casing to thereby allow breaking of the casing. Mounted on front portion 175 is a locking mechanism 106 which when closing the casing moves into its locking position to retain the front and rear portions 175 and 161 in precisely axial alignment when the casing is closed. The barrel 95 is slipped into a sleeve 101 which has its outside provided with a coarse thread 102 threadedly engaging a corresponding inner thread of a sleeve 99 slidably but non-rotatably mounted in front portion 175. The rear end of sleeve 99 is screw connected to a block 98 in which the cartridge chamber 96 is provided. That end of the barrel 95 which faces the block 98 is provided with steps 185, 186 which precisely fit into corresponding steps of the block 98. A further ring or annular member 163 is slipped over the sleeve 101 which receives the front end of the barrel. The annular member 163 is connected by means of a pin 164 to the sleeve 101 so that it cannot rotate relative thereto. A spring 91 has one end thereof in engagement with the annular member 163, while its other end rests against a ring 100 connected to the casing portion 175. In this way the spring 91 continuously urges the interconnected members 163 and 101 forwardly. The casing portion 175 is provided with a window 104 through which the ring or annular member 163 is visible and accessible from the outside. The outer surface of said ring 163 is preferably provided with a graduation. The arrangement furthermore comprises a spring 111 having one end thereof in engagement with the sleeve 99, while its other end abuts a shoulder of the sleeve 101 so that the thread 102 is held under load and any play of said thread is eliminated.

The operation of the driving tool shown in FIG. 1 is as follows:

By releasing the locking device 106, the casing is opened, and both casing portions 161 and 175 are tilted relatively to each other which operation is usually called the breaking of the casing. The stud to be driven is then passed from the rear through the cartridge chamber into the barrel, whereupon the cartridge is inserted into the cartridge chamber 96. Thereupon the casing is closed again until the locking device 106 becomes effective and interlocks the two casing portions 161 and 175. Prior or after the loading of the tool, by rotation of the annular member 163 accessible and visible through the window 104, the desired driving power is set. When the annular member 163 is rotated, the sleeve 101 non-rotatably con. nected to the annular member 163 screws in the thread 102 more or less forwardly so that the annular spaces between the steps 185, 186 of the barrel and the block 98 open more or less. FIG. 1 shows the position of the barrel when said spaces are completely closed, which position corresponds to the setting for maximum driving power. FIG. 2 shoWs a position in which the barrel is screwed outwardly to a certain extent so that the first annular space at the step 185 is somewhat opened. This means that a portion of the powder gases can enter said last mentioned annular space whereby the driving power is somewhat reduced. The surfaces perpendicularly arranged with regard to each other and pertaining to the steps prevent, however, the powder gases from entering the space 186 which space is thus still ineffective in this position of the barrel. FIG. 3 shows another position according to which the barrel is still further screwed outwardly. As will be clear from FIG. 3, in this position the annular spaces 185 and 186 and the space immediately therebelow are open so that the powder gases can enter these three annular spaces whereas the other annular spaces are still ineffective. Preferably the height of the steps decrease from the step of the greatest diameter up to the step of the smallest diameter as shown in the drawing whereby the annular spaces will open one after another. The further the barrel is screwed forwardly by rotating the annular member 163, the further will the powder gases be able to enter the succeeding annular spaces and the more will the driving power be reduced until the annular stepped spaces are open to such an extent that the powder gases can pass right into the space 187. In this position, the lowest driving power is obtained which by further opening of the stepped space would not be noticeably changed. A preferred form of construction is one in which the angle between the exit direction of the powder gases through the annular channels and the direction of movement of the firing pin in the barrel is less than 90.

In order to prevent the powder gases from passing from the space 187 into the space between the barrel 95 and the sleeve 99, and particularly in order to prevent a soiling of the thread 102, a seal 188 is provided between the space 187 and said thread. The said seal consists of grooves cut into the barrel and provided with vertical flanks. Inasmuch, as mentioned above each surface perpendicular to its direction of movement offers a very high resistance to the powder gases, these grooves suflice in order to prevent the powder gases from penetrating into the space between the barrel and the sleeve.

The tool loaded in the above mentioned manner is locked because on one hand in the illustrated rest position, the firing pin 165 is retained in such a position by the nut 156 in which it cannot reach firing cap of the cartridge. Furthermore also the pin 171 of the release or unlocking mechanism cannot cooperate with the nose 170 of the trigger 169. In order to drive the stud in the barrel into the respective wall or the like, the muzzle of the barrel 95 is placed upon the surface into which the stud has to be driven, and the tool which is held by means of the handle 119 is pressed against said surface. As a result thereof, the barrel together with the sleeves 99 and 101 are pressed inwardly against the thrust of the spring 91. The rear end of the sleeve 99 presses the block 98 toward the rear. Inasmuch as the front end of the ring 159" rests against the front surface of the block 98 as shown in the drawing, also the ring 159 and the breech block 162 are pressed backwardly. During this movement the ring 167 the inner shoulder of which is engaged by the collar 168 of the firing pin 165 also presses the firing pin backwardly, thereby loading the firing pin spring 166. When the barrel is completely pressed inwardly, the pin 171 registers with the nose 170 of the trigger 169. Stated another way, actually the tool housing is advanced toward the surface into which a stud is to be driven, while the barrel together with sleeves 99 and 101, breech block 162, firing pin 165 and sleeve 157 remain stationary during this time, the barrel being in abutment with said surface. By so advancing the housing, the firing pin spring 166 is loaded and carries trigger nose 170 into registry with pin 171. When the trigger is now actuated, the ring 167 is moved leftwardly against the thrust of spring 153, thereby releasing the firing pin. Due to the thrust of the loaded spring 166, the firing pin is pushed forwardly and hits 7 the firing cap of the cartridge so that the latter is ignited and the stud is driven into the body upon which the muzzle of the barrel was placed. The recoil brings about that the cartridge is discharged rearwardly from the cartridge chamber 96, the breech block 162 being thrown backwardly against the thrust of spring 172. As soon as due to the reaction of the spring 172, the breech block comes to a stop, the friction locking mechanism consisting of the roller 173, the incline 174 and the groove 155 in the breech block becomes effective and prevents the forward movement of the breech block. Thus, following the firing, a space remains between the block 98 and the breech block 162 in which there will be found the discharged cartridge. If after releasing the locking device 106 the casing is opened or broken, the pin 179 is pressed inwardly by the cam 178 whereby the roller 173 is pushed backwardly and the friction locking mechanism is released. The breech block 162 now due to the thrust of the spring 172 springs forwardly so that the cartridge will be thrown out when the casing is broken. As soon as the breech block has again reached the position shown in FIG. 1, the ring 167 can due to the thrust of spring. 153 again move in rightward direction (with regard to FIG. 1) so that its inner shoulder again abuts the adjacent shoulder of the collar 168 of the firing pin. All parts now have again reached their starting position.

In order to allow the driving of studs of different sizes while retaining the same cartridge chamber, the barrel is arranged exchangeably. When the casing is open, the block 98 may be removed by unscrewing it from sleeve 99 whereupon the barrel can be pushed backwardly and can likewise be removed. T 0 this end, it is necessary to release the device shown in FIG. 4 which prevents the barrel from axial displacement. This device consists of a ring 107 which is displaceable in a direction transverse to the longitudinal axis of the barrel. The ring 107 is continuously urged rightwardly (with regard to FIG. 4) by means of a spring 108 and is arranged to engage a groove 110 in the barrel 95. For purposes of removing the barrel, the ring 107 is pressed leftwardly by manually pressing the pin 109 inwardly, the inward end of the pin normally being in sliding contact with the ring 107. T he barrel can then be withdrawn from the casing and can be replaced by another barrel. In this way it is possible by means of cartridges of the same size to obtain not only different driving power depending on the material into which and the depth to which the stud is to be driven but it is also possible to drive studs of different sizes. If in this connection studs are employed which have a diameter greater than the inner diameter of the cartridge chamber, it is necessary for purposes of introducing such studs either to remove the block 98, or such studs must be introduced into the barrel from the muzzle thereof and then by means of a rod must be moved into the correct position in the rear portion of the barrel.

Accidents which could happen if when releasing the shot, the casing is not completely closed are made impossible because the locking device acts as an additional safety device. As long as the locking device is not in its complete locking position, the hook 106 will be in the path of the block 98 and in this way will prevent the barrel from being pressed inwardly which in turn prevents the firing of the stud. This is because the right angle pivoted corner portion of hook 106 when in incomplete locking position will be situated in the path of movement of block 98 with respect to the front portion 175 of the casing and will impinge against the rear end of block 98. In order to prevent the powder gases from entering between the breech block 162 and the ring 159 'whereby the release mechanism might become soiled, the outer surface of the breech block is provided with sealing grooves 191 which act in the same manner as the sealing grooves 188 in the barrel.

It is, of course, understood that the present invention is, by no means, limited to the particular constructions described in the foregoing specification and shown in the accompanying drawings, but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In an explosively actuated stud driving tool having a barrel with a bore through which a stud is expelled and a cartridge chamber for an explosive cartridge at the breech end of said barrel, the improvement which comprises said cartridge chamber being defined by a cartridge =block positioned adjacent to the breech end of said barrel, said block and barrel being adjustable separably in an axial direction with respect to each other, said barrel and cartridge block being provided with correspondingly engaging annular steps each having an axial and a radially transverse face at their abutting portions to define therebetween, when moved apart, a hollow annular step-shaped expansion chamber of variable volume for -freely expanding into said barrel gases from a cartridge exploded in said chamber.

2. Improvement according to claim 1 wherein the axial height of the steps of said step-shaped expansion chamber is progressively reduced in order in the direction toward the breech end of said tool to form successively openable pockets in said chamber.

3. Improvement according to claim 2 wherein the length of the steps of said step-shaped expansion chamber is reduced in order in the direction toward the breech end of said tool.

4. Improvement according to claim 1 wherein said barrel and said cartridge block together are additionally positioned in said stud driving tool for limited reciprocating axial movement with respect to said stud driving tool, said stud driving tool having a gas-tight chamber and a breech block sealingly slidable in said gas-tight chamber and axially movable with respect to said barrel and said cartridge block and normally resiliently urged by the force of resilient means into abutment with the breech end of said cartridge block, said breech block carrying a firing pin and being operable upon said limited axial movement of said barrel and said cartridge block with respect to said stud driving tool in the direction of the breech block by urging means to move said firing pin into engagement with a cartridge positioned in the cartridge chamber defined by said cartridge block to bring about firing of said cartridge, said breech block being slidably arranged to move away from said cartridge block in said gas-tight chamber in response to a predetermined pressure developed by the powder gases of said cartridge following the firing thereof suflicient to overcome the urging force of said resilient means.

5. Improvement according to claim 1 wherein said barrel is interchangeably mounted in said stud driving tool by releasable securing means.

References Cited in the file of this patent UNITED STATES PATENTS 891,778 Mertens June 23, 1908 990,475 Cuccurullo Apr. 25, 1911 1,190,352 Winks July 11, 1916 1,864,374 Romberg et a1 June 21, 1932 2,030,803 Temple Feb. 11, 1936 2,359,515 Fanger Oct. 3, 1944 2,38 ,053 Fanger Aug. 21, 1945 2,518,395 Sopris Aug. 8, 1950 2,533,851 Temple Dec. 12, 1950 2,622,243 Temple Dec. 23, 1952 2,665,421 Temple Jan. 12, 1954 2,677,823 Magnuson May 11, 1954 2,697,830 Erickson Dec. 28, 1954 2,801,416 Evans et al Aug. 6, 1957 2,849,715 Kopf Sept. 2, 1958 FOREIGN PATENTS 768,859 France -1 May 28, 1934 

